Specularity only work on bottom of dif

I'm new to tgea, and I've been experimenting with Materials. When I add the following material definition (for the texture that's used on the docks) the specularity only shows up on the bottom of the object. When I flip it over, it switches to the other side. Does anyone know what I'm doing wrong?

new Material(WESTroof)
{
    mapTo            = "WESTroof";
    baseTex[0]       = "WESTroof";
    bumpTex[0]       = "WESTroof_NRM";
    
    version = 2.0;
    
    pixelSpecular[0] = true;
    specular[0]      = "1.0 1.0 1.0 1.0";
    specularPower[0] = 32.0;
};

Btw, the normal map was generated with CrazyBump.